1. Field of the Invention
The present invention relates to out-of-line underwater safing and arming device which is armed at a predetermined ambient pressure when placed under water and when removed is automatically safed.
2. Description of Prior Art
Associated with almost every explosive device is a safing mechanism. Where such a device is for use under water such as, for example, shown in U.S. Pat. No. 4,395,951 with Hinely as inventor, the arming feature involves a submersion of the device in water--water then providing a "water column" which forms in effect a piston which reacts to pressure generated by an explosive actuator or squib. When so-fired, the Hinely patent device is then totally expended and releases some type of package in the water which, for example, might be used for mine sweeping. If not actuated, Hinely teaches that upon removal of the device from the water, water empties out of the device by means of gravity preventing any further actuation.
The Osburn U.S. Pat. No. 4,158,334 discloses an out-of-line safe/arm device used for initiating an explosion deep in a geothermal wall. It utilizes an air chamber and spring which when compressed enough by being lowered to a certain depth in the well lines up a detonator. If it is not fired but raised again, then the spring returns the device to an out-of-line safe position. Here there is no actual water arming but merely a response to the ambient pressure which would normally be supplied by a liquid medium. Thus, the Osburn device does not actually depend upon the use of a water column for arming. And, of course, Hinely while illustrating the use of a water column for use in arming an explosive device, since it does not have an in-line, out-of-line operational mode, but rather is a one-shot release device, its water column concept is not readily adaptable to the in-line, out-of-line technique of Osburn.
Thus, it is a general object of the present invention to provide an improved out-of-line underwater safing and arming device and method therefor.